1. Field
Embodiments of the present invention relate to a secondary battery.
2. Description of Related Art
Secondary batteries are rechargeable, unlike primary batteries which are typically not rechargeable. Typical secondary batteries include a low capacity battery having a battery cell in the form of a pack and used in portable small electronic devices such as cellular phones and camcorders, and a high capacity battery including tens of battery packs connected to one another and used as a power source for driving a motor, e.g., of hybrid vehicles.
Secondary batteries are manufactured in various shapes such as a cylindrical shape and a prismatic shape. Electrolyte and an electrode assembly formed by inserting a separator as an insulator between a positive electrode plate and a negative electrode plate are installed in a case, and a cap assembly provided with electrode terminals is installed on the case, so as to form a secondary battery.
When a secondary battery is over charged, excessive heat is generated, or electrolyte is decomposed to increase the inner pressure of the secondary battery, and thus, the secondary battery may be burned or exploded. Accordingly, a secondary battery having high safety is needed.